This invention relates to an apparatus for recording an information signal at each of a plurality of divided areas provided by dividing one track along the scanning direction of a rotary head. This occurs such as when an 8 mm video tape recorder is exclusively used as an apparatus for recording and/or reproducing a PCM (pulse-code-modulated) audio signal. A pilot signal is recorded and/or reproduced for tracking. This pilot signal is used in the reproducing mode by a rotary head when the pilot signal for tracking is superimposed upon the information signal.
The 8 mm video tape recorder can operate in a recording mode in which an audio signal is frequency-modulated, and is mixed with a color video signal so as to be separable from the color video signal and then can be recorded. In an additional optional mode, this audio signal is pulse-code-modulated and recorded in an area separate from that of the color video signal, and one track is formed by both the PCM audio signal and the color video signal.
FIG. 1 shows one example of a rotary head assembly of the 8 mm video tape recorder, and FIG. 2 the tape format thereof according to the prior art.
In FIG. 1, reference letters HA and HB represent record and reproduce rotary magnetic heads. These record and reproduce rotary magnetic heads are made different in the azimuth angles of their recording gaps, and are mounted at an angular spacing of 180.degree. on the periphery of a rotary drum 1 so as to slightly project from the peripheral surface of the rotary drum 1.
The rotary magnetic heads HA and HB are rotated at a frame frequency (30 Hz) in the direction shown by an arrow 3H. A magnetic tape 2 is wrapped around the periphery of the drum 1 over an angular spacing of more than 221.degree., and is transported at a constant speed in the direction shown by arrows 3T.
Accordingly, on the tape 2, there are alternately formed by rotary heads HA and HB tracks 4A and 4B 221.degree. long to thereby record the signal as shown in FIG. 2. On the tracks 4A and 4B, in an area AP having an angular range of about 36.degree. (including a margin for recording the PCM audio signal in the so-called after-recording mode and a guard band area), there is recorded a PCM audio signal with a compressed time base associated with one field period of the video signal. In a next area having an angular range of 180.degree., there are recorded a color video signal of one field period, an FM audio signal, and a pilot signal for tracking. The remaining area having an angular range of 5.degree. is assigned as a spare period for the time when the head is detached from the magnetic tape 2.
As described above, the 8mm video tape recorder is capable of recording and/or reproducing the PCM audio signal. So, in view of the above mentioned aspect, a technique has been proposed for enabling the 8mm video tape recorder to be used as a PCM audio signal recording and/or reproducing apparatus by using a color video signal recording area AV as a PCM audio signal recording area (see U.S. patent application, Ser. No. 463,337, filed on Feb. 2, 1983, incorporated herein by reference).
Specifically, the area AV having the angular spacing of 180.degree. in which the video signal and the like are recorded is five times as long as the PCM area AP having the angular spacing of 36.degree.. So, by equally dividing the area AV by 5, there are provided 5 divided track areas AP2 to AP6 shown by .circle.2 to .circle.6 per track 4A, in addition to the original PCM audio signal track area AP1 indicated by .circle.1 as shown in FIG. 3. Then, the PCM audio signal of one channel, that is the audio signal of one field period which is pulse-code-modulated and time-base-compressed, is recorded on and/or reproduced from each of 6 divided track areas AP1 to AP6.
Therefore, in this case, since the audio signal of one channel can be recorded and/or reproduced at the unit of each area, the audio signal of 6 channels can be recorded and/or reproduced, making the recording time (capacity) 6 times as long as that in the prior art (this technique will be hereinafter referred to as a multi-PCM).
It is sufficient that a PCM processor to be used in the multi-PCM can be a one channel processor that is used by the conventional 8 mm video tape recorder, because the recording and/or reproducing is carried out at each divided track area. In this case, the pilot signal for tracking is recorded and/or reproduced at each divided track area (see Japanese Laid Open Patent Application No. 59-43682).
As described above, in the multi-PCM mode, the pilot signal for tracking is recorded and/or reproduced at the unit of each divided track area so that the recording tracks from the channels .circle.1 to .circle.6 are rarely aligned rectilineally along the scanning direction of the rotary head as shown in FIG. 3, but are arranged arbitrarily as shown in FIG. 4.
If the recording and/or reproducing is carried out at the unit of each divided track area, that is, at the channel unit, it is not necessary that the divided recording tracks be aligned as shown in FIG. 3.
In order to reproduce a slave tape by using a recorded tape as a master tape, there is known a method in which the modulated signal recorded is then picked up by the rotary head and recorded on the slave tape without being demodulated, to thereby carry out the high speed dubbing operation. This high speed dubbing method does not require a demodulation, but only requires a master tape on which the signal was recorded in a given recording pattern.
Therefore, if it is possible that the signals from the tracks .circle.1 to .circle.6 on a track are reproduced by one scanning of the rotary head, and the reproduced signals are recorded similarly on the slave tape. Thus, the dubbing can be carried out with good efficiency. For this purpose, the divided recording tracks must be aligned along the scanning direction of the rotary head.
Furthermore, since the exclusive PCM audio signal recording and/or reproducing apparatus is capable of recording the signals of multi-channels, a mode is possible, where the sound of each of the respective musical instruments in the orchestra, for example, is separately recorded on each of the channels. Upon reproducing, the recorded signals of 6 channels are simultaneously reproduced as if the respective musical instruments were played in concert. In this case, the tracks each having 6 channels must be aligned along the scanning direction of the rotary head.